Sanitary napkin having control element with gel-forming material



July 4, 1967 J. DE MERRE 3,329,145

SANITARY NAPKIN HAVING CONTROL ELEMENT WITH GEL-FORMING MATERIAL Filed Feb. 12. 1965 INVENTOR Z50/v c/ HEM/Pas BY n Malia/ ATTORN y United States Patent O M' 3,329,145 SANITARY NAPKIN HAVING CONTROL ELE. MENT WITH GEL-FURMING MATERIAL Leon J. De Merre, Highland Park, NJ., assignor to Johnson & Johnson, a corporation of New Jersey Filed Feb. 12, 1965, Ser. No. 432,191 Claims. (Cl. 12S-290) This invention relates to absorbent products, land more particularly, is directed to improvements in sanitary napkins.

Absorbent products such .as sanitary napkins usually consist of a core of one or more layers of highly absoribent, relatively `dense fibers around which there is a fluid permeable, soft, knitted, woven or nonwoven wrapper. The core is conventionally made of layers of bers such as carded cotton webs, air layered cellulosic fiber webs, comminuted wood pulp bats, tissue pulp or like materials which are highly absorbent. Also, sanitary napkins have been made with a fluid impermeable baille sheet positioned within the wrapper. Conventonally, these fluid impermeable baflle sheets are of a plastic material most usually a sheet of polyethylene. These fluid impervious plastic baille sheets are usually located on the bottom side of the highly absorbent fibrous core where any fluids which are not 'absorbed 'by the fibrous mass in the core are prevented from passing through to the wrapper overlying the bottom side of the pad.

By such a construction, sanitary napkins have been substantially improved in their ability to absorb large quantities of menstrual fluids while at the same time resisting strike-through ,and side-spread failure. It has lbeen primarily this strike-through and side-spread failure that has plagued napkin users. Accordingly, consumer demand has required considerable research effort directed toward solution of this most perplexing problem.

While the above-described plastic film barrier has proved to be the most effective solution to strike-throu gh and side-spread failure, other, even more effective means would be desirable. For example, sometimes napkins must be used during a period of time when they are subjected to excessive quantities of fluid. While the plastic film barrier initially prevents passage of fluids therethrough when sufficient quantities of menstraul fluids @build up behind the fluid barrier, there is possibility of a spill over the longitudinal side edges of the fluid barrier where they extend upwardly over the sides of the absorbent core. In such instances, the menstraul fluids and solid or semisolid constituents thereof pass through to the wrapper covering the portion of the absorbent core which is away from the side V positioned against the body of the user.

By the present invention, I have found a novel mechanism and means for substantially eliminating strikethrough and side-spread failure in sanitary napkins and which also provides more effective absorption of menstrual fluids in the absorbent core portion of the napkin.

According to the present invention, I have provided a sanitary napkin having a menstrual fluid flow control element positioned in the absorbent core portion. The control element consists generally of one or more layers of normally highly absorbent fibrous or pulp material which is impregnated with one or more protein reactive agents which upon contact with fluids and proteinaceous materials forms a coagulum. By coagulation of the proteinaceous material in menstrual fluid, the coagulating agents constituting a portion ofthe control elementare also effective to entrap the other nonproteinaceous -components of the menstrual discharge and lock up or entrap the aqueous fluid phase. In essence, a lbarrier is formed in situ Within the absorbent core portion of the sanitary napkin immediately upon interception of the control element :by menstrual fluids. As the area of coagulum builds up, addi- 3,39,l45 Patented July 4, 1967 tional menstrual fluids impringing thereon spread laterally over the top surface of the control element forming additional coagulum thereby preventing penetration of fluids and proteinaceous constituents of menstrual fluids from passing therethrough. Additionally, any pool of fluid which might be `formed at the top of the formed-in-situ impervious coagulum becomes semisoli-dilled thus preventing leakage through the control element and spill over at the side edges of the formed-in-situ-coagulum barrier.

These and other features kand attendant advantages of the present invention will be apparent from the description hereinafter contained when taken in conjunction with the accompanying drawings in which:

FIG. l is a perspective view of an absorbent sanitary napkin which is shown partially open to illustrate the incorporation of the invention, and f FIG. 2 is a cross sectional view taken on line 2-2 of FIG. 1.

Referring now to the drawings, a sanitary napkin 1f) incorporating the invention includes a relatively thick, elongated absorbent core 12 enclosed within .a liquid pervious wrapper 14 whose ends extend beyond the ends of the absorbent core to provide the usual attachment tabs 16. The absorbent core can be about 21/2 inches wide and 8 inches long and can consist of one or more layers of fibrous material such :as carded cotton webs, air-layer cellulosic fiber webs, comminuted wood pulp bats, tissue pulp or like materials which are highly absorbent. There can also be included within the absorbent core 12 one or more layers of semirepellent sheets such as sulflte, creped paper or absorbent layers of bleached sulte paper wadding and the like. The entire core assembly is enclosed Within a liquid pervious wrapper 12.

In the embodiment shown in the drawings, there is positioned intermediate the absorbent core 12 and the fluid pervious wrapper 14 on one side of the napkin, a fluid control element 18 which consists of a layer of fibrous material impregnated with protein reactive chemicals. The fluid control element 18, to be `described in greater detail hereafter, is illustrated in the drawings in a so-called one- Way napkin. That is to say, the positioning of the fluid control element intermediate the core and the wrapper at one side of the napkin is worn with the side opposi-te the fluid control barrier positioned against the body. However, it is to be understood that a so-called two-way napkin can be made in accordance with the present invention by positioning fluid control element 18 within the absorbent core so as to have highly absorbent librous material on both sides thereof. In this instance either side of the napkin can be positioned against the body of the wearer, tand all the advantages of the invention are obtained.

It is preferred that fluid control element 18 extend transversely across the width of the core 12 and longitudinally the full length of the core 14.. Additionally, fluid control element 18` can extend upwardly partially covering or completely covering the longitudinal side edges of core 12 in the one-way napkin. Alternatively, strips of fibrous material impregnated with the protein reactive chemicals of the present invention can be placed along and coextensive with the longitudinal side edges of the core 12 in abutting relationship to the control element 18 positioned interiorly of the core 12 in a two-way napkin. In this manner, side edge spill-over as well as strikethrough of menstrual fluids and proteinaceous components therein is prevented. v

Menstrual fluid control element 18 can consist of any suitable, absorbent material such as one or more plies of wood fiber pulp, cellulose wadding, regenerated cellulose sponge, absorbent creped tissue, fibrous woven or nonwoven webs or the like. Particularly preferred, is a Wood pulp hat of Natchez fiber.

The protein reactive chemicals used in the present invention must be those which react with the proteinaceous constituents of menstrual fiuids to form a coagulum. Protein precipitating salts while effective for forming a barrier to the passage of some of the proteinaceous constituents of menstrual fluids are ineffective as a barrier to the fluid constituents thereof. In fact, menstrual fluids with some of the proteinaceous constituents thereof removed by protein precipitating chemicals become less viscous and thereby pass more readi-ly through the absorbent layers of the napkin on the side opposite to the precipitating chemicals. 4

I have found by using a protein reactive chemical which forms a coagulum the fluid constituents of menstrual fiuids are also entrapped by the menstrual fluid control element. That is to say, the protein reactive chemical reacts with the proteinaceous constituents of menstrual fiuids to form insoluble protein complexes which cannot be removed from the fluid carrier by dialysis.

When the menstrual fluid control element is intercepted by menstrual fiuids, the protein reactive agents of the present invention react with the proteinaceous materials thereof to form the coagulum of the above-described protein complex and in which the fluid portion of the menstrual fluids is also entrapped.

The protein reactive chemicals which I have found acc-omplish the abovedescribed results are phosphotungstic acid, tannic acid and sulfosalicyclic acid, each an admixture with pectin. The fibrous elements forming the menstrual fiuid control element are impregnated with a mixture consisting of the pectin and one or more of the abovenamed acids.

The amount of pectin and acid used in the fibrous control element ranges from about 12% to about 20% pectin and from about 0.3% to about 1% of the acid constituent .based upon the weight of the fiber. Most preferred, is a fibrous element impregnated with about 15% pectin and about 0.5% of the acid.

In the preferred forms, three types of menstrual fiuid control elements are prepared by forming dry homogenates each consisting of one of the following admixed constituents:

(a) Natchez fiber 84.5%; pectin 15%; phosphotungstic acid 0.5%.

(b) Natchez fiber 84.5%; pectin 15%; tannic acid 0.5%.

(c) Natchez fiber 84.5%; pectin 15%; sulfosalicylic acid 0.5%.

About 60 grains each of the above compositions are formed into bats approximately 23/2 inches wide, 8 inches long, and 3716 of an inch thick. Each of the above-prepared bats are placed at the bottom of an absorbent core and enclosed within a fiuid pervious wrapper of nonwoven material. Samples of each of the above-prepared napkins are subjected to clinical testing where it is found in every instance when menstrual fiuid penetrates through the core of the napkin to reach the fiuid control elements, immobilization of the menstrual fiuid occurs at the top of the control elements in the form of a brownish coagulum and the portions of the napkins on the opposite side of the control elements remain dry. There can be found no trace of proteinaceous material or fluid at or near the cover portion of the sanitary napkin positioned on the bottom side opposite the control element.

Attempts to separate by dialysis the proteinaceous constituent from the coagulum entrapped by the control elements are unsuccessful.

As seen from the foregoing description and examples setting forth illustrative embodiments of the invention there is provided a napkin which is economical to make, which effectively prevents strike-through of fiuid absorbed by the napkin, which prevents side-spread failure of the napkin and which effectively absorbs and retains menstrual fluids and the proteinaceous constituents thereof. lt is apparent that variations, modifications and changes in the foregoing illustrative embodiments and examples can be made while still remaining within the spirit and scope of the invention.

What is claimed is:

1. A sanitary napkin comprising a relatively thick elongated absorbent core, a liquid pervious cover around said core and a fluid control element positioned interiorly of said napkin, said fluid control element comprising a relatively thin layer of fibrous material containing in admixture pectin and an acid selected from the group consisting of phosphotungstic, tannic and sulfosalicylic acids.

2. The invention of claim 1 wherein said control element is positioned intermediate said absorbent c-ore and said cover on the bottom of said napkin.

3. The invention of claim 1 wherein said control element is positioned interiorly of said absorbent core.

4. A sanitary napkin comprising a relatively thick elongated absorbent core, a liquid pervious cover around said core and a fiuid control element positioned interiorly of said napkin, said fiuid control element comprising a relatively thin layer of fibrous material containing in admixture from about l2 to about 20% pectin and from about 0.3 to about 1.0% of an acid selected from the group consisting of phosphotungstic, tannic and sulfosalicylic acids based upon the weight of the fibers in said control element.

5. The invention of claim 4 wherein said pectin and said acid are contained in said control element in an amount of about 15% and about 0.5% respectively based upon the weight of the fibers in said control element.

6. The invention of claim 4 wherein said control element is positioned intermediate said absorbent core and said cover on the -bottom of said napkin.

7. The invention of claim 4 wherein said control element is positioned interiorly of said absorbent core.

8. A sanitary napkin comprising a relatively thick elongated absorbent core, a liquid pervious cover around said core and a fiuid control element positioned interiorly of said napkin, said fiuid control element comprising a relatively thin layer of fibrous material being substantially equal in width and length to the width and length of said absorbent core, and containing in admixture from about 12 to about 20% pectin and from about 0.3 to about 1.0%

of an acid selected from the group consisting of phos photungstic, tannic and sulfosalicyclic acids based upon the weight of the fibers in said control elements.

9. The invention of claim i8 wherein said pectin and said acid are contained in said control element in an amount of about 15% and about 0.5% respectively based upon the weight of the fibers in said control element.

10. The invention of claim -8 wherein said control element is positioned intermediate said absorbent core and said cover on the bottom of said napkin.

11. The invention of claim 8 wherein said control element is positioned interiorly of said absorbent core.

l2. A sanitary napkin comprising a relatively thick elongated absorbent core, a liquid pervious cover around said core, a first fiuid control element comprising a relatively thin layer of fibrous material being substantially equal in width and length to the width and length of said absorbent core and being positioned interiorly of said napkin, second control elements comprising relatively thin layers of fibrous material positioned along the coextensive with the longitudinal side edges of said absorbent core, said first and second control elements containing in admixture from about l2 to about 20% pectin and from about 0.3 to about 1.0% of an acid selected from the group consisting of phosphotungstic, tannic and sulfosalicylic acids based upon the weight of the fibers in said control elements.

13. The invention 4of claim 12 wherein said pectin and said acid are contained in said control elements in an amount of about 15% and about 0.5% respectively based upon the weight of the fibers in said -control elements.

5 14. The invention of claim 12 wherein said first control 2,440,141 element is positioned intermediate said absorbent core 2,542,909 and said cover on the bottom of said napkin. 3,078,849 1S. The invention of claim 12 wherein said first control 3,121,427 element is positioned interiorly of said absorbent core. 5 3,124,135 3,146,168 References Cited 3,249,109

UNITED STATES PATENTS 1,950,957 3/1934- Wilhelm 12S-2,90

6 Donovan 128`-285 DeWet 12S-290 Morse 128-290 Mosier 12S- 285 Olson 12S-290 Battista 167-484 Maeth et a1. 128-268 RICHARD A. GAUDET, Primary Examiner.

2,331,271 10/1943 Gilchrist 12s-29o l0 C F-ROSENBAUM,EXa/t1fnef 

1. A SANITARY NAPKIN COMPRISING A RELATIVELY THICK ELONGATED ABSORBENT CORE, A LIQUID PERVIOUS COVER AROUND SAID CORE AND A FLUID CONTROL ELEMENT POSITIONED INTERIORLY OF SAID NAPKIN, SAID FLUID CONTROL ELEMENT COMPRISING A RELATIVELY THIN LAYER OF FIBROUS MATERIAL CONTAINING IN ADMIXTURE PECTIN AND AN ACID SELECTED FROM THE GROUP CONSISTING OF PHOSPHOTUNGSTIC, TANNIC AND SULFOSALICYLIC ACIDS. 